A screw electrode was implanted on the intracranial dura mater of guinea pigs, and after dark adaptation, 50 photic stimuli at the interval of 10 sec were given with a xenon lamp intensity of 2.0 joule, and the ERG and VEP were recorded. The ERG showed no change after 3 months and 24 applications of ethylacetate in the control group, but in the TDI-treated group α and β waves showed prolonged latency and decreases in amplitude. The VEP showed no remarkable change in the control group, but in the TDI-treated animals some changes were seen in P1-N1 amplitude. These changes suggested that repeated exposure to TDI causes a decline in the retinal function.